Blue Oak is a prominent character in the Pocket Monsters (Pokémon) series. He is the rival of the main protagonist, Red, and is known for his competitive nature and skilled Pokémon training. Blue is the grandson of Professor Oak, a renowned Pokémon researcher, which has inspired him to become a strong and knowledgeable Pokémon Trainer himself. Throughout the series, Blue challenges players at various stages, often serving as a benchmark for their progress. His character development spans from a cocky rival to a mature and respected Pokémon Champion.